This invention relates to the recovery of heavy, viscous, immobile oil from a subterranean formation. More particularly, it relates to a three stage oil recovery process wherein steam huff and puff is used to produce oil and create voidage in the formation, and in situ combustion in the top of the formation is used to create communication between injection and production wells, and steam injection is used to drag oil out of the formation.
Within subsurface formations reside vast quantities of viscous, immobile oils not recoverable by conventional oil production procedures. Various techniques have been proposed for heating such formations to reduce the viscosity of such hydrocarbons so that the oil becomes mobile and can be flowed into a production well. Three known techniques steam huff and puff, steam drive and forward in situ combustion are pertinent to this disclosure. In this disclosure, these three known techniques are combined and carried out in a special sequence and manner. The steam huff and puff and in situ combustion stages are carried out for additional or different purposes.